It sounds like you need to learn to forgive...not for their sake, but for your own. When you hold it all inside of you and don't let it go, it eats at you and changes you as a person. In a way, it chains you down. I'd find books on forgiveness and learning to be slow to be offended, etc, and see if any help you.
I'd also look and see if they are really messed up people who are repeatedly hurting you and you need to give yourself space from them. Maybe there is a reason you are feeling so hurt!
Whatever it is, I hope you figure out how to find that peace inside of you. You deserve it. Don't ever let anyone treat you in a way that ruins who you are inside. Let their poison out of you and keep yourself mentally and emotionally healthy.
ADDED: Just read the other comments. I hadn't even thought of depression. That is a good suggestion too. Maybe there is some reaosn you are feeling depressed? Therapy might help (and I'm someone who thinks everyone would benefit from therapy from the RIGHT therapist!).